Tilted Forum Project Discussion Community - what trouble can NOT properly breaking in an engine cause?

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what trouble can NOT properly breaking in an engine cause?

due to reasons out of my control (moms appts, ford dying...her needing jeep...) ive had to drive my suburban to work all week, since the day after i got it running with the new engine...

i read somewhere that you need to run it at certain RPMs for certain ammounts of time...i looked all over and couldnt find any information on breaking in a 350...anyone know of anything?

Well breaking in all engines (pushrod operated) is the same... Here is the proper procedure

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1) Safety first! If the car is on the ground, be sure the emergency brake is set, the wheels are chocked, and the transmission cannot fall into gear. Next verify that all hoses are tight and that both the radiator and radiator over flow jar/tank are full and have been filled with the proper anti-freeze and water mix.
2) Before starting your engine for the first time, add one pint of engine oil supplement ( EOS¹) to the crankcase oil and then check the oil level. Once this has been done, prime the oil system with an oil pump primer tool. Make sure number 1 cylinder is on TDC compression stroke, and install the distributor.
3) Adjust the distributor timing roughly by hand for a quick start up and smoothest idle possible.

4) When the engine first starts, verify that the engine rpm is at a safe level and that the timing is set near or at 30° before top dead center (BTDC). Run the engine speed between 1,500 and 2,500 RPM’s, varying the engine speed up and down with-in this range, to prevent overheating of the exhaust valves and the exhaust system. This should be done with no-load on the engine and for the first 30 minutes of operation.
5) After the first 30 minutes of the engine running, set the ignition timing according to the timing specifications. Now would be a good time to check thoroughly for leaks.

6) Adjust the carburetor settings, if necessary.
7) Drive the vehicle with varying speeds and loads on the engine for the first 30 miles. Be sure not to use a lot of throttle or high RPM.
8) Run five or six medium-throttle accelerations to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.
9) Run a couple hard-throttle accelerations up to about 3,800 RPM (55 to 60 MPH), then letting off in gear and coasting back down to 20 MPH.
10) Change the oil and filter with recommended oil (10w30SG in most cases) and filter.
11) Drive the next 500 miles normally, without high RPM’s (below 3,800 RPM), hard use, or extended periods of high loading.
12) Change oil and filter again.

13) Your engine is now ready for many happy cruising miles!

Did you actually rebuild the entire motor, or just put a new topend on? The directions above are for a complete new motor top to bottom. Most of those directions pertain to the bottom end parts break-in. If you only changed a cam and heads then you are good to go after the 30 minute cam break-in session.

A problem with not breaking an engine in properly, would probably quick wear on the internals, so they wont last as long. Kinda like if you get new brakes, if you dont break them in, and do heavy braking after you get them, theyll wear down faster and just cut down the life of the pads, or in your case the engine. Im just guessing.

It's a crate GM long block, so all i put on it was the intake, etc.

it sounds like the way i have been driving it is pretty much as it should have been done.

Studies have shown that an engine thraped to within an inch of its life from day one will actually pull harder, perform better over its now significantly shortened lifespan.

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Originally Posted by castex

Studies have shown that an engine thraped to within an inch of its life from day one will actually pull harder, perform better over its now significantly shortened lifespan.

that is because when you start off with a new engine, the cylinder walls have a cross-hatch pattern on them... if you don't run the engine like a madman on those first few miles what happens is the piston rings do not get worn down by the cross-hatch pattern, you want the rings to get worn down so they fit and seal with the cylinder perfectly....

the cross-hatch pattern goes away after a short time wether or not the rings have been worn down accordingly...

at all automotive plants, after they assemble your car/bike/snowmobile whatever they start it up and rev the crap out of it... so there goes the whole do not cross 3K RPM for the first 100 miles crap...

oh, change the oil after the frist 10 miles. Microscopic peices of metal are floating around in there, and if you dont get them out, they will end up inside bearings and and you'll get more friction in them, i.e. less power...

Rev the living hell out of it as soon as it's warmed up, otherwise the rings won't seal properly. Ideally, as soon as you put the engine in the car, you would dyno it about 6 times, letting it cool after every two runs, and starting at about 60% throttle, moving up to 80% for the second, and 100% for the rest.

Next, do an oil purge, put in new oil, and change it again after 100 and 500 miles, then go on a regular schedule.